Roberts Anthony J, Goodman Brian S, Reck-Peterson Samara L
Department of Cell Biology, Harvard Medical School, Boston, United States Astbury Centre for Structural Molecular Biology, School of Molecular and Cellular Biology, University of Leeds, Leeds, United Kingdom
Department of Cell Biology, Harvard Medical School, Boston, United States.
Elife. 2014 Jun 10;3:e02641. doi: 10.7554/eLife.02641.
Cytoplasmic dynein powers intracellular movement of cargo toward the microtubule minus end. The first step in a variety of dynein transport events is the targeting of dynein to the dynamic microtubule plus end, but the molecular mechanism underlying this spatial regulation is not understood. Here, we reconstitute dynein plus-end transport using purified proteins from S. cerevisiae and dissect the mechanism using single-molecule microscopy. We find that two proteins-homologs of Lis1 and Clip170-are sufficient to couple dynein to Kip2, a plus-end-directed kinesin. Dynein is transported to the plus end by Kip2, but is not a passive passenger, resisting its own plus-end-directed motion. Two microtubule-associated proteins, homologs of Clip170 and EB1, act as processivity factors for Kip2, helping it overcome dynein's intrinsic minus-end-directed motility. This reveals how a minimal system of proteins transports a molecular motor to the start of its track.DOI: http://dx.doi.org/10.7554/eLife.02641.001.
细胞质动力蛋白驱动货物沿着微管负端进行细胞内运输。在各种动力蛋白运输事件中,第一步是将动力蛋白靶向到动态微管的正端,但这种空间调节的分子机制尚不清楚。在这里,我们使用来自酿酒酵母的纯化蛋白重建动力蛋白向正端的运输,并使用单分子显微镜剖析其机制。我们发现两种蛋白质——Lis1和Clip170的同源物——足以将动力蛋白与Kip2(一种向正端移动的驱动蛋白)偶联。动力蛋白由Kip2运输到正端,但它不是被动的乘客,会抵抗自身向正端的运动。两种微管相关蛋白,Clip170和EB1的同源物,作为Kip2的持续性因子,帮助它克服动力蛋白固有的向负端的运动性。这揭示了一个最小的蛋白质系统如何将分子马达运输到其轨道的起点。DOI: http://dx.doi.org/10.7554/eLife.02641.001 。